Alternating-current-motor-controlling apparatus.



A. SUNDH.

ALTEBNATING CURRENT MOTOR CONTROLLING APPARATUS.

APPLIUAT-ION FILED 001:1 31. 1908.

1,012,477. Patented Dec.19, 1911.

4 SHEET HBIIT 1.

A. SUNDH. ALTERNATING UURRENT MOTOR CONTROLLING APPARATUS.

APPLICATION .FILED OCT. 31. 1908, 1,012,477. Patented Dec. 19, 1911.

4 SHEETS-SHEET 2 A. SUNDH.

ALTERNATING CURRENT MOTOR CONTROLLING APPARATUS.

APPLIGATION FILED DOT. 31, 1908 1,012,477, Patented Dec. 19,1911.

A. SUNDH.

ALTERNATING CURRENT MOTOR CONTROLLING APPARATUS.

APPLICATION FILED 001131, 1908.

Patented Dec. 19, 1911.

4 BHEETB-BHEET 4.

UNITED STATES PATE NT. OFFICE;

AUGUST SUNDH, 0F YONKERS, NEW YORK, A SSIG 'NOR T0 OTLSELEVATOR COMPANY.OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ALTERNATING-CURRENT-MOTOR-GONTROLLING APPARlATUS.

Specification 0t Letters Patent Patented Dec. 19, 1911.

Application filed October 31, 1908. Serial No. 460,508.

To all wlwm it may concern:

it known that I, AUGUST- SUNDH, a citizen of the United States, residingat Yonkers, in the count of 'Westchester and State of New York, laveinvented a new and useful Improvement in Alternating-CurrenblllotonGontrolling Apparatus, of which the following is aspecification.

My invention relates to alternating cur rent motor controllingapparatus, and one of its objects is the provision of improvedmeans forvarying the starting resistance to eflect gradual acceleration in thespeed of the motor.

One of the'specific ob'ects of the invention is to provide improveaccelerating apparatus for alternating current motors of theinduction'type.

Other objects of the invention will appear hereinafter, the novelcombinations of elements being set forth in the appended claims.

Beferring to the drawings, Figure 1 is a diagrammatic viewof analternating current inductionmotor and-controlling mechanism therefor;Fi 2 is a similar view showing a modification; Fig. 3 is a sideelevation partly in section of an electro-magnet swltch mechanism usedin the control of the motor; Fig. 4 is a front elevation of the same;and Fig. 5 is a rear elevation partly in section on the line 5-5 of Fig.3.

In Fig. 1. a three-phase induction motor M is shown adapted to receivecurrent through the leads a, b, a connected to a suitable source ofcurrent supply. The lead b is connected directly to the middle bindingpost 6 of the motor stator, and the leads a and c are adapted. to beconnected through the potential switch P, reversing switches R and R.and the leads a and c to the outer bindin posts a and c of the stator.The rotor o the motor is connected by the three conductors I, 2 and 3 tothe outer tcrmmals of a sectional starting resistan e Y. controlled bythe electro-magnetic switch devices or controllers A. B, C and D. Thesedevices are substantially alike in mostparticulars and their generalconstruction, as shown diagrammatically in Figs. 1 and 2. is

as follows. The device A. for example,com-- prises a base 4 on which ismounted a lower electro-magnet 5 having a spool or winding 6,anflan'npper electro-magnet 7 havinga winding 8. The armatures l2 and 11of the in a c osed position. When the armature .12

of the magnet 5-is in its attracted position, as shown, the arm 21 holdsthe switch lever open and the spring 22 compressed. The lower magnetcoils 6, 6", 6 and 6 are connected in series in a circuit across two ofthe terminals orcollector rings of the rotor .so that they will allreceive the same current, which will be proportional to the voltage atthe collector rings. In this instance these coils are connected byconductors 23 and 24 to the conductors land 2. The upper magnet coils 8,8", 8 and 8 are arranged to be connected in parallel circuits across twoof the stator terminals, as b and c', and are controlled by the severalswitches aswill fully appear in the description of the operationhereinafter. The parts are shown in their normal position of rest. Tostart the motor. the switchlever of the manual switch- S is movedifiircgca ple, to the left, so'that the segment 2fi'cngagcs the stationarycontacts 26. 27 and 98." This-establishes a circuit through thgmagnetcoil 31. which circuit may be'traccd from theleadb through conductor 29.contacts 26. 25. conductor 30. magnet coil 31 to the lead 0. The magnetcoil 31 therefore receives current and oncrutcs to close the switch P.thereby establishing a circuit through the magnet coil of the reversingswitch R as follows: from the lead b through conductor 29. contacts 26.25. 27. conductor magnet coil 33 of reversing switch R. conductor 34.and contacts 35 to thelead a. The niagnct coil 33 lifts its core andcloses the reversing switch R which connects the lead a through thecontacts 35. conductor 34. reversing switch contacts 37 and conductor ato the terminal a. of the motor and connects the lead c through thecontacts 38. conductor 39. contacts 40 and conductor 0' to the terminal0'' of the motor.

The stator now "eceivcs current and induces a ciirrent in the rotor,causing the motor to to close.

start, the current in the rotor being kept within a safe limit by thestarting resistanoe Y which is, all infcircuit at this time. The lowermagnet coils 6, 6", 6 and 6 now receive current proportional'to thevoltage between the conductors 1 and 2. The magnet coil 8 also receivescurrent when the reversing switch has operated, as it is connected in acircuit between the conductors b and c as follows: from the'conductor' 0through contacts 38, conductor 39, contacts 40, conductor 0', conductor41, magnet coil 8, conductor 42, switch contacts 4,3, and conductor 44,to conductor 6. The current through this circuit is substantiallyconstant so long as the main line potential. remains the same. Thecurrent through the lower magnet coils, however, gradua y decreases asthe speed of the motor increases 'When the motor starts the strength ofthe magnet 5 is suilicient to hold its armature against the opposingpull of the upper magnet 7, but as the speed of the rotor increases thecurrent through the coil 6 is gradually reduced and'the magnet weakeneduntil the upper magnet 7, aided by the spring 22, pulls its core in,permitting the switch 13 The closing of the first switch short-circuitsthe upper sections 45,46, 47 of the starting resistance through theconductorg 8, 49. 50, connected respectively to the switch contacts 17,18 and 19, and permits the motor to accelerate. The closing of thisswitch also stablishes a circuit through the magnet c il 8", whichcircuit may be traced from the conductor '2), through conductor 44,contacts 16, 15, magnet coil 8", and conductor 41 to conductor c'. Theoperation of the lever 9, as above noted, moves the armature 12 awayfrom its magnet and thereby decreases the magnetic -inductance in thecoil 6 and ermits an increase of currentthrough t e lower magnetcoils,thus bringing back the amount of flow 'of current in the lower magnetsto what it was when the motor started. As the speed of the motorincreases, the current through these coils decreases.again until themagnet- 8' is able to effect the operation of the switch device B. Thisoccurs when the current through the lower magnet coils is about the samein strength as when the switch device A operated. The operation of theswitch device B short-circuits the Sections 51. 52, 53 through theconductors 51", 52", 53", and also closes a circuit through the magnetcoil 8 by way of the cont-acts lii 'and 16 The operation of the switchdevice B again reduces the self-induction in the lower magnet coils andpermits the current to increase to a value substantiall equal to what itwas when the motor starte As the speed of the motor increases urther,the switch device C operates and shortcircuits the sections 54, 55, 56of the starting resistance, closes a circuit through the magnet coil 8,and reduces the inductance 1n the lower magnet coils to again efi'ect anincrease of current in the lower magnets.

Finally, as the speed increases still further, the switch device D isoperated. This shortcircuits the entire startingresistan'ce by contheconductors 1, 2 and 3 together througi the conductors 57, 58 and 59-andthe contacts 17, 18 and 19, and permits the motor to attain maximumfullnormal speed. The 0 eration of the switch lever 13 separates t 1econtacts 4:3 and thus opens the circuit through the upper magnet coil 8and permits the weight bf the lever 9 and the armatures 11 and 12 toopen the switch device A. This separates the contacts 15 and 16 andopens the circuit through the magnet coil 8", permitting the switchdevice B to be opened and in turn effect the opening of the switchdevice C. The circuit through the magnet coil 8 remains closed, however,by reason of the holding circuit established through the contacts 15 and16". The motor may -now run at full normal speed with all the startingresistance short-circuited, the switch device D in its closed positionand the devices A, B and C open, and no current flowing in thecontrolling'circui ts except through the magnetcoil 8. The circuit forthe lower magn'et coils is short-clrcuited by the bridging contact 19".It will thus be seen that but little current is used in the controllingmech anism during the normal operation of the motor. As the lowermagnets are each designed to operate with about the same currentstrength, the current through thein windings only varies withincomparatively I narrow limits. That is, as the speed of the motorincreases and the potential throu h the circuitof the magnet coilsdrops, t e inductance of the circuit is decreased step by stepasthemagnets operate successively, so that the current strength is keptapproximately uniform. This arrangement of the magnet coils in seriesand so that the current strength is kept up as the speed of the motorincreases, forms an important feature of the present invention, as itsecures a reliable and satisfactory operation of the controllingdevices. These lower magnets may be considered magnetic dash-pots, asthey all curstopping the motor. It will ondary winding 60 of thecont-rolling mechanism is practically independent of moderate variationsin, the main line potential, as the current strength ..in both the upperand lower opposing electro-mag'net windings is main line voltage. If,for example, the voltage on the main line should drop while the magnetcoils 8" and 6" current, the strength of the current in the coil 8"wouldbe reduced in the same propor' tion. The potential in the rotorcircuits beingalso roportional to the main line potential, t e currentin the magnetcoil 6* would be'correspondingly reduced, so that theopposing upper and lower magnets would be weakened to the same extentand the operation of the switch device B unaffected.

In Fig. '2, the construction is substantially like thatshown in Fig. 1,except that the current for the lower magnet coils 6, 6", 6, 6 issupplied by a transformer T. These coils are connected in series withthe serthe transformer. The primary windin 61 is connected in circuitwith the'condilctor 1 between the rotor and the starting resistance andreceives all the current [lowing through the conductorl. .A conductor 57connects the contact 17 with the conductor 1 between the motor andtransformer, and when the switch device D has operated the'conductors57', 5S and 59 connect the conductors 1, 2 and 3 and shorbcircuit theprimary of the transformer and th starting resistance.

- Except as above noted, the operation is the openings 65 to means of abolt v through :1 lug 70 formed on the arm 7 of contact with its magnetand prevents res ondingly threaded opening -in same as described inconnection with Fig. 1.

In Figs. 3, 4 and 5, I have illustrated the construction of one of theelectro-magnotic switches, such as A. The base 4-, on which all of theswitches may be mounted it desired. isvmade of slate or other suitableinsulating material. A bracket 62 is secured to one face oi the base 4by bolts (33 which extend through the base and also form a securingmeans for a double frame. member or casting 64 on the opposite side ofthe base 4 and provided with screw-tln-eaderl receive the thleaded endsof the bolts 63.

a. bearin pin 14 mounted in the arms t"? of the brac et 62. Also pivotedon the pin- 14 bet-ween the lugs 66 is an arm 20 which extends into'anopening in the base 4. This arm is adjustahly connected to the switchlever 13 for movement therewith by 09. 'This bolt. extends lms 20, andis screw-threaded to engage a corthe swltch lever 13. A lock nut 71serves to clamp the head of the bolt against the lug and lock the boltin adjusted position. The bracket 62 is iotmedovith a housingproportional to the were receiving The switch lever 13 formedwithbearing lugs 66 1ournalod on" 72 to receive the coil spring 22 whichbears against the arm 20 and tends to close the switch. The switch lever"13 carries metallic contacts 17 and 18 insulated from the switch leverby plates orbushings 75 and 76 of insulating material. are ado pted toengage a air of carbon contacts 19 and 19 mounte' in a metal holder orclamp 79 and clamped in position b .a

clamp bolt 80. The holder 79 ispivote ,at 81 to a bracket 82' providedwith an integral rod or stem base and -formin a binding post for theconductor 50. Tie contacts 17 and 18 are connected by flexibleconductors 48' and 49' to the binding osts 73 and 74 for the con ductors18 an 49. The-insulating plate 76' is extended as shown in Fig. 4 toform a support. for the contact 15 which engages the contact 16 when theswitch is closed.

The contact 16 is slidablymountcd in a support or holder 84 and isyieldingly held in its outward position by a coil spring 85 surroundinga stem 86 formed on the contact 1G. The upper magnet comprises a bodyportion 87 of laminated iron clamped between the upper surface of thecasting 6t and an upper casting 88. 'Clam ing bolts 89 and 90extending-through lugs formed on the fragile members, and rivets 91 'and92 extendirtg through the laminations and through arms 93 and 94 oi the83 extending through the These contacts frame members, serve to clampthe parts firmly in position. The construction of the lower magnet issimilar, the laminated body portion 95 being clamped between the lowersurface of the casting 64 and a lower frame casting 96 bymeans of bolts-97, 98 and rivets 99 -and 100. The armature lever 9 is pivoted at 10between lugs 101 and 102 formed on the casting 041 Screw bolts 103, 101,having conical bearing ends to-fit conical bea ring surfaces in thelever 9, are adjustable in said lugs to take up wear or lost motion inthe bearings and are held in adjusted position by loclc nuts 105 and106. A screw bolt 107, adjustable in a lug 108 on the lower end of thelever 9, forms a stop for the lever when in the position shown. Byadjusting this stop the air p of the lower magnet may be varied so thatthe device will operate at any 'desired 5 eed of the motor. A lock nut107 holds t e stop in its adjusted position. An adjustable stop for theu per end'of the armature lever is formed iy a screw bolt 109 threadedinto a lug 110 on-the upper casting 88, and heldin a justed positionby-a lock not 109'. This stop serves to hold the armature out sticking.The lever 9 carries upper and lower cores or armatu'res 11 and 12adepted to be drawn into the upper and lower anagnet spools 8 and 6,respectivel The lever 9 has an integral arm '21 w ih etten'ClS into theopening 68 in the base 4 in osition to en e-the'under surface 0' the arm20. Itwill be observed that the weight of the armature lever 9 and thearmatures is nearly all on one side of the pivot and tends to swing thelower end of the lever inwardly. The lever 9 made quitewide and massiveand the weight is suflicient to compress the spring 2 2-and open theswitch lever whenever the magnets are denergized. The heavy armaturelever arranged in this way not only permits the use of a strong enoughspring 22 to effectually operatethe switch lever, but also has sufhcientinertia to prevent atoo quick or sudden operation of each separate unitof the controller. When the upper magnet coil receives sufiicientcurrent to operate the lever 9, aided by the spring 22, the arm 21 ismoved out of contact with the arm 20 so that vibrations of the armaturelever due to current alternations cannot be transmitted through saidarms to the switch lever. The pivoted contact holder 7 9 permits anequalization of the pressure between the contacts 19, 19 and thecontacts 17, 18, so that a good electrical connection is secured.

Various changes in the details of construction and a. rangement of partsmight obvi- 'ously be made by those skilled in the art without departingfrom the spirit and scope of the invention, and I wish therefore not tobe limited to the exact construction disclosed. 7

\Vhat I claim as new and desire to secure by Letters Patent of theUnited States is 1. The combination with an alternating current motor ofthe induction type, of coils connected to the primary source of current,additional coils connected in series in a secondary of the motor,resistance in parallel with said additional coils in the secondarycircuit, and means controlled by said coils for varying the resistance.

2. Thecombination with a multiphase motor of the induction type, ofcoils connected in arallel to the primary source of current, additionalcoils connected in series in a secondary circuit of themotor, startingresistance, and means controlled by said coils for varyin saidresistance.

3. T ecombination with a multiphase motor of the induction type,- ofcoils connected in a circuit leading from the primary source of current,resistance in the secondary circuit of the motor, additional coils inseries witheach other in a circuit connected directly across two of theterminals of the secondary, and devices controlled and operatedsuccessively by said coils for successively cutting out sections of thestarting resistance at predetermined speeds of the motor. a

4. The combination with an alternating current motor of the inductiontype, of resistance in the secondary circuit thereof, and a pluralit ofeIectro-responsive devices for successive y short-circuitmg saidresistances as the speed of the motor increases, said electro-responsivedevices comprising singlephase coils connected to the primary andadditional single-phase coils in series with each other in a circuitconnected directly to two of the motor terminals.

' 5. The combination with an induction motor, of magnet coils in aprimary circuit of the-motor, opposing magnet coils arranged in seriesin a secondary circuit of the motor,

a starting resistance in (parallel with said last-named coils, and speeregulating mechanism controlled-by the magnet coils.-

6.'The combination with an alternating current motor, of resistance inthe secondary circuit of the motor, and means for controlling saidresistance comprising a plurality of series-connected windings in acircuit in parallel with the resistance.

7'. The combination with an alternating current motor, ofstartingresistance in the secondary circuit of the motor, a plurality ofelectro-magnets having their windings connected in series in a circuitin parallel with the resistance, and means controlled by saidelectro-magnets for reducingthe starting resistance in the secondary crcuit.

8. The combination with an alternating cu rrcnt motor ofthe inductiontype, of elmtro-magnets having their windings connected to the primarysource of current, magnetically independent electro-magnets having theirwindings connected in :series in a secondary circuit of the motor,resistance in the secondary circuit of the motor, and

means dependent upon the combined action of the first and second-namedelectro-magnets for controlling the resistance.

9. The combination with an alternating current motor of the inductiontype, of starting resistance in the secondary circuit of the motor, aplurality of coils connected to receive current from the secondary ofthe motor, means to-maintain the current in said coils approximatelyuniform as the s eed of the motor varies, and means contro led by saidcoils for successively short-cireuiting sections of the startingresistance.

10. The combination with an alternating current motor of the inductiontype, of coils connected to receive current from the motor secondary,means for preventing 'a substantial variation in the current in saidcoils as the secondary potential varies, and devices associated withsaid coils for controlling the acceleration of the motor.

11. The combination with an electric motor of the induction type, ofcoils connected to receive current from the secondary of the motor,means for reducing the impedance in the circuit or circuits of saidcoils a proximately in proportion to the drop in voltage of said circuitor circuits as the speed of the motor increases, and starting resistancecontrolled by said coils.

12. The combination with an alternating current motor'of the inductiontype, of coils connected in series in a circuit across the terminals ofthe motor secondary, means for varyin the impedance in'said circuitsubstantia ly in proportion to variations in the voltage between saidterminals and devices controlled by said coils for eti'ecting theacceleration of the motor.

13. The combination with an alternating current motor of the inductiontype, of a plurality of electro-magnets having their COllSCOIHLGCtBd inseries in a circuit connect ed to receive current from the motorsecondary, devices controlled by said magnets and o erat-ivesuccessively to effect the acceleration' of'the motor, said magnets andcoils being'designed toreduce the induclanee 'in the circuit of thecoils as said devices operate and maintain an approximately uniformcurrent in the coils as the speed of the motor increases.

14. The combination with an alternating current motor of the inductiontype, of a plurality of successit'ely operable electro- 'magnets,means'for connecting the coil of each magnet to receive current fromthzdpriniary upon the operation of the prec ing -magnet a plurality ofelectro-magnets connected in series in a circuit of the motor secondaryand opposing the operation of the first-named electro-magnets, andresistance in a circuit of the motor and controlled by the operation ofsaid electro-inagnets.

